Hydrometer

I have a question regarding hyrdrometer readings. I understand that all beers will have different readings when finished, but is there a general range for all finished products?

I'm asking this question because I'm afraid my fermentation is complete, but maybe there is still some sugar in the wort. How can I determine if there is sugar in the wort? I understand that I could simply taste it and see if its sugary, but I'm sure it's possible to have smaller amounts of sugar and not be able to taste it.

Depends on the beer really. You know it's done when you have the same FG 3 days in a row. Unless it's stuck. Then there are other tactics. Generally speaking you should be able to achieve at least 70% attenuation. Cheers!!!

hamiltont said:

Depends on the beer really. You know it's done when you have the same FG 3 days in a row. Unless it's stuck. Then there are other tactics. Generally speaking you should be able to achieve at least 70% attenuation. Cheers!!!

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Is it possible, though, that you will get the same reading three days in a row (due to fermentation stopping), but in actuality, the fermentation never completed?

Also, I have a stupid question. What is attenuaton?

^ what he said As an aside, I wouldn't bother taking the reading until at least 2 weeks after your brew day. I usually wait for 3 weeks or more. No harm in letting it sit.

AImhoff88 said:

Is it possible, though, that you will get the same reading three days in a row (due to fermentation stopping), but in actuality, the fermentation never completed?

Also, I have a stupid question. What is attenuaton?

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Yes, its possible, although unlikely. If you are concerned, after you take the readings, let us know the gravity (hydrometer) reading and your recipe and process (especially how long you have let it sit and at what temperature), and we can give you advice. In my case, it will be poorly conceived and best ignored, but others will be able to help.

Attenuation is a measurement of how much of the sugars in the wort the yeast ate up. That's not the scientific definition, of course.

AImhoff88 said:

Is it possible, though, that you will get the same reading three days in a row (due to fermentation stopping), but in actuality, the fermentation never completed?

Also, I have a stupid question. What is attenuaton?

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With practice you'll know the difference between "done" and not. Generally, a reading that doesn't change under 1.022 is done unless it's a specialty beer.

Attenuation is a number, given as a percentage, that tells you the amount of sugar converted to alcohol. Most of the time, you can expect 67-80% of the sugars to be fermented. So, in a 1.050 OG beer, 75% attenaution would give you 1.012.

What they all said. A good rule of thumb is 75% attenuation for most beers. Attenuation is the apparent degree of fermentation which is simply 1 minus the final gravity ponts(FG) divided by the starting gravity points (OG) times 100. That would be 1-(12/50) X 100 in Yoopers sexy example. The specific gravity is a ratio of the density of the solution to pure water. Apparent attenuation is used because it is not the true or real degree of attenuation due to the presence of alcohol in the solution which skews the reading. That, however, is nothing to be concerned about. You are simply checking how well the beer finished out vs. what was intended with the recipe. I've been drinking stiffly mixed hot buttered rum, so I may not have this exactly right. I'm getting an early start on Christmas eve. Less than six hours to go. Most of the presents are wrapped and next up is a home made eggnog with Mount Gay Barbados Pure Cane Sugar Rum. It was on sale today. Could not pass it up!

Catt22 said:

That would be 1-(12/50) X 100 in Yoopers sexy example . . . I've been drinking stiffly mixed hot buttered rum, so I may not have this exactly right.

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I always find math, especially division and percentages, to be hot, too.

What are you talking about?

:cross:

I made a "brewing" spreadsheet from info I've gathered over the years that really makes these things quick & easy. It includes a Batch Sparge water calculator, Strike Water temperature calculator, Hydrometer reading calculator adjusted for temp, Pre-Boil Original Gravity calculator, Alcohol calculator and a calculator for blending beer. Shoot me a PM with your email address & I'll send it to you. Cheers!!!

I unfortunately did not take a hydrometer reading when I first put the wort in the fermenter. It's been roughly 48 hours now and I just took a reading. I got 1.012. The krausen has already disappeared, but the beer I poured into the hydrometer tube was quite murky and I could clearly see bubbles rising.

How could my reading be so low despite fermenting only 24 hours and the beer so murky and bubbly?

AImhoff88 said:

I unfortunately did not take a hydrometer reading when I first put the wort in the fermenter. It's been roughly 48 hours now and I just took a reading. I got 1.012. The krausen has already disappeared, but the beer I poured into the hydrometer tube was quite murky and I could clearly see bubbles rising.

How could my reading be so low despite fermenting only 24 hours and the beer so murky and bubbly?

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If you only brewed two days ago (am I understanding that right?), then my advice is to chillax, as the kids say. Really, just walk away from it and check on it again in two or three weeks. Don't take another hydrometer, don't open the lid, just let it be.

AImhoff88 said:

I unfortunately did not take a hydrometer reading when I first put the wort in the fermenter. It's been roughly 48 hours now and I just took a reading. I got 1.012. The krausen has already disappeared, but the beer I poured into the hydrometer tube was quite murky and I could clearly see bubbles rising.

How could my reading be so low despite fermenting only 24 hours and the beer so murky and bubbly?

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That is rather unusual, but without knowing your OG, it's difficult to say. The beer will nearly always bee murky and bubbly at the 24 hr point. There will likely be considerably CO2 still in solution. Let the sample sit overnight if you still have it and see what it reads in the morning. The bubbles may be throwing off the hydrometer reading considerably. It may also still be bubbling in the morning.

I've read that FG could be as low as 1.005 so I wouldn't worry. Let it sit for longer.

1) Sometimes they go quick, each fermentation is different.
2)Just because you're at or near your expected fermentation doesn't mean that it's done. Letting it sit for a few weeks, at least, allows that murk (probably mostly yeast) to fall out of suspension. Let it sit in the primary for a month and it will get very clear on it's own and the yeast will also consume fermentation by products that can cause off flavors.
3)The bubbles are dissolved CO2 coming out of solution.
4)1.012 is a good number for a final gravity for many brews, but 24 hours is nowhere near long enough for clearing, conditoning or anything else. Even if it's at final gravity it still needs to sit longer.

But the people posting above are right, the more specifics you can provide around recipes, process and fermentation conditions, the better information or help you'll get from the community.

patience, patience, patience!

Does lower FG usually mean higher alcohol content, since alcohol is lighter than water?

AImhoff88 said:

Does lower FG usually mean higher alcohol content, since alcohol is lighter than water?

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Generally speaking and in relative terms, yes. The next question would be higher than what? The specific gravity will drop as the sugars are consumed by the yeast and alcohol is produced in the process. Yes, alcohol is lighter than water and that is the reason that it is possible for the gravity to drop below 1.000. That would be quite unusual for a beer, but IIRC it's not that rare for a mead or cider to do so. I'm not experienced with meads and ciders, so I may be a little off base on that, but I think I read that somewhere once upon a time.